Les Disher

RGB 15 minutes each X 3 for a total of 135 minutes exposure 155mm AP operating at F5.25. Images stacked in RegiStar and processed in Photoshop Elements

RGB 6 minutes each for a total of 18 minutes exposure 155mm AP operating at F5.25. Images stacked in RegiStar and processed in Photoshop Elements.

RGB 250 minutes each, for a total imaging time of 750 minutes 155mm AP refractor working at F14. Images stacked in RegiStar and processed in Photoshop Elements

Two sets of images taken March 17 & 18
RGB 15 minutes each using an AP 155mm at F5.25
Images combined using RegiStar, with final processing in Photoshop Elements

I took this image on Saturday, March 17 from latitude 37 degrees 48 minutes, longitude 119 degrees 04 minutes near June Lake, California, in the eastern Sierras, so I had the advantage of about 12 extra degrees of latitude.
Exposures were RGB 15 minutes each using a 155mm AP at F5.25
Final processing was one in Photoshop elements.

Photo Session # 375, September 24, 2006, at the Merritt Star Party at Loon Lake.
The first exposure began at 11:28 PM PDST, and the last exposure ended at 12:15 AM on the morning of Sept. 25.
RGB was 15-15-15 using an SBIGST8i operating at -15C.
The OTA was an AP 155mm operating at F5.25 (ie. with a focal reducer).
The guide scope was a Meade 90mm operating at F10 using an SBIG ST4 to make the corrections.
The mount was an AP1200GTO.
Limiting visual magnitude (ie. transparency) that night was estimated at 6.5 on a scale of 10.
Seeing (atmospheric scintillation) was 3.5 on a scale of 5 (with 0 being perfectly still air).
There was no discernible wind at the telescope throughout the exposure period.
The temperature dropped from 8.2 degrees C to 7.8 degrees C over the exposure period (ie. remained very stable), and the relative humidity increased from 67 to 70 percent.
There was no fog, and almost no dew.

Each of the RGB images had dark frame subtracted. They were combined in CCDSoft and contrast enhanced in Photoshop Elements.

Photo Session # 380, October 21, 2006, at home in Courtenay
It was the first of two colour composite images of the Cocoon I took that night.
The first exposure began at 9:22 PM PDST, and the last exposure ended at 10:55 PM.
RGB was 30-30-30 using an SBIGST8i operating at -20C.
The OTA was an AP 155mm operating at F5.25 (i.e. with a focal reducer).
The guide scope was a Meade 90mm operating at F10 using an SBIG ST4 to make the corrections.
The mount was an AP1200GTO.
Limiting visual magnitude (ie. transparency) that night was estimated at 5.5 on a scale of 10 (it can be 6.5+ at my location at best)
Seeing (atmospheric scintillation) was 2.5 on a scale of 5 (with 0 being pefectly still air).
There was no discernible wind at the telescope throughout the exposure period.
The temperature dropped from 6.0 degrees C to 5.4 degrees C (ie. remained very stable) over the exposure period, and the relative humidity increased from 86 to 88 percent (I monitor the temperature in case there is enough of a change that a focus shift might occur).
There was a noticeable fog, but it was not a heavy layer, extending from the ground up about 40 meters, and there was pronounced dewing on the outside of the optical tube.

Each of the RGB images had bias, dark and flat field frames subtracted. They were combined in CCDSoft and contrast enhanced in Photoshop Elements.

I thought you might like to see this image of the Pelican Nebula I took a little over a year ago using film.
I used a 155mm refractor at F7. Exposure was 206 minutes using Kodak E200 slide film. Image was taken July 31, 2005 at June Lake, California. The slide was scanned and processed in Adobe Photoshop Elements.

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